X0306 4 2018-03-09 0 0001394056 ONE STOP SYSTEMS INC OSS 0001283973 REARDON JOHN RALPH 2235 ENTERPRISE STREET #110 ESCONDIDO CA 92029 1 0 0 0 Common Stock 2018-03-09 2018-03-09 4 F 0 20902 1.00 A 145422 I By: Reardon Family Trust dated August 31, 2011 Employee Stock Option (right to buy) 1.00 2018-03-09 2018-03-09 4 M 0 25000 0.00 D 2009-04-01 2018-03-31 Common Stock 25000 0 D Represents a "net exercise" of outstanding stock options. The reporting person received 20,902 shares of common stock on net exercise of option to purchase 25,000 shares of common stock. The reporting person forfeited 4,098 shares of common stock underlying the option in payment of the exercise price, using the closing stock price on March 9, 2018 of $6.10. Mr. Reardon holds joint voting and investment control of the trust with his wife Dawn Reardon. /s/ John Reardon 2018-03-13